Art of forming structures of concrete and similar materials.



. UNITED STATES PATENT @FFICE'.

ERNEST LESLIE RANSOME, OF NEIV YORK, N. Y.

ART OF FORMING STRUCTURES OF CONCRETE AND SIMILAR MATERIALS.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filerl Tanuary 4, 1905. Serial No 239,617.

To (LZZ whom it may concern:

Be it known that I, ERNESTLESLIE RANsoMn, a citizen of the UnitedStates, and a resident of the city of NewYork, borough of Richmond, inthe county of Richmond and State of New York, have invented new anduseful Improvements in the Art of Forming Structures of Concrete andSimilar Materials, of which the following is afull, clear, and exactdescription.

The invention is applicable to the formation of various structures ofconcrete and like plastic materials, but it is especially applicable toconcrete floors, pavements. and other structures in which the materialis laid in sheet or so-called monolithic form.

The concrete floors are generally formed of two layers, a base or underlayer and an upper or top layer, these layers being of different gradesorcomposition suited, respectively, to the location of the layer.Heretofore difficulty has been experienced in properlyjoining theselayers so as to form a true bond between them, making a rigid solid massas distinguished from two distinct layers resting one on the other. Inorder to effect this bond, it has been necessary to place the upperlayer upon the lower layer before the latter fully sets or hardens.Numerous practical objections exist to this method of procedure, sinceit occasions costly delays, and often even under the most skilledsupervision the bond so formed is weak, and an imperfect floor is theresult. Further, the top layer has been placed in position oftentimeswhen the conditions render it practically impossible to make awellfinished floor or other surface.

The underlying object of my invention is to enable the top layer to beplaced in position after the bottom layer has been well set or hardened.This allows the operator to choose his own time for finishing the floorand to put the top layer in position at that time and under thoseconditions whichare best suited to perfect results.

In carrying out my improvement I first place the bottom or base layer inposition in the usual manner, and I allow the same to completely set orharden. IVhen the concrete sets, its surface is formed by a hard denseskin or covering, the presence of which has heretofore rendered itimpossible to bond or unite the top layer with the bottom layer of thefloor. According to my invention after the bottom layer has set andhardened and when it is desired to place the top layer in position andfinish the floor I wash this hardened surface of the said bottom layerof the concrete with an acid of such a nature as will attack and removethis hardened skin or surface of the bottom layer. For this purpose Iprefer to employ a solution of hydrochloric acid. This acid attackingthe said surface of the bottom layer or base removes this hardened skinand renders the bottom layer capable of cohesion with the top layer,which is to be placed thereon. Before placing the top layer, however, itis best to remove the excess of acid, the resultant salts, anddisintegrated material by washing the surface of the bottom layer withwater. Then the top layer of the concrete is formed in plastic conditionover this prepared surface of the bottom layer, resulting in a perfectbond between the two layers and a true monolithic or integral structure.The top layer of plastic cement may be placed in position in any desiredmanner for instance, by floating it onto the base or bottom layer, as isusual.

l/Vhen the top layer is a mortar of neat cement, I deem it best and Iprefer to rub or brush a portion of this neat cement into the preparedsurface of the bottom layer, and before this portion sets I apply therest of the layer in any of the usual ways by float or otherwise. Whenthe upper layer consists of a substance other than neat cement mortar,or when it consists of acement mortar rich with cement, but containingsand or other mineral aggregate, I consider it-best and I prefer tofirst rub or brush into the prepared surface of the base or bottom layera thin mortar of neat cement and then bed the finishing layer of coarsermortar or cement into this mortar before it sets.

\Vhile the invention is especially adapted for laying floors or otherhorizontal surfaces, I desire it understood that I am not limited tothis work, and I also would point out that the invention may be employedwith good results in laying tile floors where the ceramic tiles arejoined by cementing to the concrete base or bottom layer. In this casethe upper surface of the bottom layer is prepared as before describedand the top layer or setting of the tiles formed thereon as beforedescribed, this layer serving to unite the tiles to the base or bottomlayer. I would also point out that the excess of acid and salts and thedisintegrated material resulting from the action of the acid on theconcrete surface need not necessarily be removed by washing. Other meansmay be employed for the same end. For instance,

these substances may be removed by brushing or scrubbing the preparedsurface.

The term cement herein employed refers specifically to Portland cement;butobviously the invention is not limited to this precise substance andmay be utilized in connection with other cement having similarcharacteristics with regard to bonding and the hardened set surface ofwhich may be dissolved, disintegrated, or otherwise affected by theaction of an acid or otherwise.

Having thus described the preferred form of my invention, whatl claim asnew, and desire to secure by Letters Patent, is

1. The improvement in the art of forming structures of concrete or thelike, which consists in forming a layer of plastic material containingcement and permitting the same to set or harden, in removing portions ofthe hardened surface of said layer by the action of an acid applied tosaid surface, and in forming a second layer of plastic materialcontaining cement, over said surface of the first layer, and permittingthe second layer to harden, whereby to form a perfect bond between thetwo layers.

2. The improvement in the art of forming structures of concrete or thelike, which consists in forming a layer of plastic material containingcement and permitting the same to set or harden, in removing portions ofthe hardened surface of said layer by the action of a hydrochloric acidapplied to said surface, and in forming a second layer of plasticmaterial containing cement, over said surface of the first layer, andpermitting the second layer to harden, whereby to form a perfect bondbetween the two layers.

3. The improvement in the art of forming structures of concrete and thelike, which consists of forming a layer of plastic material containingcement, and permitting the same to harden, in removing portions of thehardened surface of said layer by the application of an acid thereto, inremoving from said surface the excess of acid and resultant salts anddisintegrated material, and in forming a second layer of plasticmaterial containing cement, over said surface of the first layer, andpermitting the second layer to harden, whereby to form a perfect bondbetween the two layers.

4. The improvement in the art of forming structures of concrete or thelike, which consists in forming a layer of plastic material containingcement and permitting the same to set or harden, in removing portions ofthe hardened surface of said layer by the action of an acid appliedthereto, in washing the surface after the action of the acid for thepurpose specified, and in forming a second layer of plastic materialcontaining cement, over said surface of the first layer, and permittingthe second layer to harden, whereby to form a perfect bond between thetwo layers.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ERNESL LESLIE RANSOME. Witnesses:

G. W. COOPER, FRANK V. LAWRENCE.

